This invention relates to methods of conducting data communications in ring-structured distributed processing networks. In particular the invention concerns a method of operating processing station systems in such networks in a locked receiving mode whereby a selected ring station may be given virtually continuous and exclusive access to the (locked) receiving station's system for transferring a variable amount of data into a program-assignable area of that system's main store.
A problem in respect to such operations is that a locked receiving station could be isolated from ring stations other than the selected station for intervals of time which are unacceptably long, "unacceptably" in the sense that the benefits derived from locked mode operation may be effectively cancelled by the network disruption caused by the isolation of the locked station from other stations requiring immediate controlling attention.
The object of the present invention is to provide a method of operating such ring station systems in the locked mode which allows the locked system to remain effectively accessible to all ring stations.